1. Field of the Invention
The present invention pertains to medical apparatus and methods and more particularly, to apparatus and methods used for treating sleep apnea.
2. Description of the Related Art
Apnea is a common sleep disorder characterized by one or more pauses in breathing or shallow breaths while sleeping The breathing pauses can last from a few seconds to several minutes and can occur 5 to 30 times or more an hour. Typically, when breathing is resumed, a loud snort or choking sound occurs that is heard by others sleeping nearby. The sudden snort or choking sound often wakes up the individual and disrupts his or her sleeping cycles thereby causing the individual to feel physically and mentally tried the next morning. Severe sleep depredation is a major symptom found in patients suffering from sleep apnea.
There are two generally type of sleep apnea—obstructive sleep apnea (OSA) and central sleep apnea, (CSA). OSA is the most common and is believed to be caused by muscles in the throat that collapse and obstruct breathing. The method and apparatus disclosed in U.S. Pat. No. 6,587,725 is used to treat OSA. CSA is less common cause of sleep apnea and is believed to be caused by imbalances in the brain's respiratory control centers.
Recently, electrical stimulation to an individual's breathing muscles has been used to treat both OSA and CSA. Typically, sensors and stimulators have been surgically implanted into the diaphragm, neck muscles, the genioglossus and the phrenic nerve. The sensors are typically coupled via an external machine to activate the stimulators when a signal is received from the sensor. A stimulating stimulating current is then delivered to the upper respiratory muscles in the neck. Normally, the sensors monitor for breathing cessation, minute diaphragm contraction, high blood carbon dioxide levels EEG patterns, and EMG patterns. Controlling sleep apnea by the sensing and stimulating various respiratory muscles is disclosed in U.S. Pat. Nos. 6,587,727; 6,770,725; 5,678,535; 5,146,918 and U.S. Patent application 2008/0109047. One drawback with using imbedded sensors and stimulators is that they must be surgically mounted inside the body, and do not prevent the apnea episode. The patient's sleep is still disturbed.
Breathing machines, such as CPAP machines, are commonly used to treat OSC and CSA apnea. Such machines create continuous positive airway pressure from a shoe box size air pump that connects to a mask worn by the patient. The mask, also called the interface, normally includes head gear, a nose piece, a mouth pieces, and tubing. It is important that the head gear, the nose piece, and the mouth piece fit properly to provide a proper seal to deliver positive airflow. Finding a mask that meets these criteria that is comfortable when sleeping and is compatible with the patient's sleeping position (back sleeper, side sleeper, and abdomen sleeper) is difficult. Because the air pump is loud, and the mask is uncomfortable, most patients who use CPAP machines rarely have uninterrupted sleep.
What is needed is an improved apparatus and method for treating apnea that prevents apnea episodes from occurring during sleep, is small, quiet, comfortable to use.